Superatom-in-Superatom [RhH@Ag₂₄(SPhMe₂)₁₈]²⁻ Nanocluster

Heterometal doping is a powerful method for tuning the physicochemical properties of metal nanoclusters. While the heterometals doped into such nanoclusters predominantly include transition metals with closed d-shells, the doping of open d-shell metals remains largely unexplored. Herein, we report the first synthesis of a [RhHAg₂₄(SPhMe₂)₁₈]²⁻ nanocluster, in which a Rh atom with open d-shells ([Kr]4d⁸5s¹) is incorporated into the Ag₂₄ framework by forming a RhH superatom with closed d-shells ([Kr]4d¹⁰). Combined experimental and theoretical investigations showed that the Ag₂₄ framework was co-doped with Rh and hydride and that the RhH dopant was a superatomic construct of a Pd atom. Additional studies demonstrated that the [RhHAg₂₄(SPhMe₂)₁₈]²⁻ nanocluster was isoelectronic to the [PdAg₂₄(SPhMe₂)₁₈]²⁻ nanocluster with the superatomic 8-electron configuration (1S²1P⁶). This study demonstrated for the first time that a superatom could be incorporated into a cluster superatom to generate a stable superatom-in-superatom nanocluster.